1. Field of the Invention
This invention relates to a method utilized to reinforce/stiffen or decorate substrates with a powder, and more particularly to a method for reinforcing/stiffening or decorating shoe uppers prior to their assembly on a shoe last.
2. Prior Art
The shoe and apparel industry have for many years provided reinforcement/stiffening means to their products. Manufacturers of pajamas, blue jeans, sports clothing, including sports equipment such as gloves, caps with visors and the like, as well as shoe manufacturers have stitched, glued or otherwise applied layers of reinforcing material to their products for a variety of reasons. It has been standard for the industry, particularly shoe manufacturers, to apply the reinforcement/stiffening means as a layer of molten thermoplastic material adherable to a shoe upper. Early attempts at reinforcing or stiffening a shoe upper have included providing preformed stiffener elements or counters, cut from sheets of material of uniform thickness, which are inserted into a shoe upper, prior to lasting. Separate moldable sheet materials softenable by heating or by solvent have been inserted in the shoe uppers prior to lasting and are shaped in the course of lasting to a desired configuration which configuration they retain by being allowed to harden before removal of the shoe upper from the last. Shoe uppers have also been stiffened by impregnating a shoe component with a solution or dispersion in a volatile liquid vehicle of hardenable stiffener materials prior to lasting of the shoe upper, the shoe upper being stiffened by hardening of the impregnating material after the shoe is lasted.
One such way of stiffening shoe uppers is shown in U.S. Pat. No. 3,316,573 to Chaplick et al, wherein a shoe upper has a selected area in which a resiliently flexible stiffener element is fluidly deposited, and heated to a moldable point, and brought to a three-dimensional configuration which it will retain on cooling.
Another arrangement for coating shoe parts is shown in U.S. Pat. No. 3,342,624 to Kamborian, wherein a stencil plate rests upon a shoe upper, a concave support surface holds the combination, whereupon a doctor blade wipes across the plate to deposit a fluid stiffener into the depression in the shoe upper.
A more recent arrangement for stiffening shoe components, is shown in U.S. Pat. No. 3,973,285 to Babson et al, comprising an arrangement for depositing a molten charge of thermoplastic on a shoe upper held in a margin clamping means.
The prior art arrangements may occasionally work well, but they have difficulty producing a stiffener of uniform thickness over seams and overlaid patterns. The adhesion of the stiffener at its edges is often poor. Rough edges, and strings or "spider webs" characteristic of the process may all be present. The machines may leak their molten material out of the connecting joints, nozzles may drool and patterns may require time and patience to change.
The materials usable in these prior art machines are limited to certain viscous flow and heat stability characteristics which necessitate careful tailoring--often comprising the performance of the final product. These specialty materials are also more costly.
Thus it is an object of the present invention to provide a method apparatus which will overcome the shortcomings of the prior art.
It is a further object of the present invention to provide a new method of applying reinforcement/stiffening or decorative means in a desired configuration to a flexible substrate such as a shoe upper or piece of cloth-type material, which configuration may be readily changed to facilitate various shoe upper patterns or styles or reinforcement/stiffening or decorative requirements of the garment with conveniently made low cost stencil tooling.
It is yet a further object of the present invention, to provide a method of operating an apparatus which will manufacture a smooth stiffened/reinforced or decorated shoe upper, or article of cloth or the like, without the inconveniences of the prior art.